Stormy fish sex Ian J. Winfield & J. Ben James Structure of presentation • Introduction • Methods • Results • Summary Introduction Introduction • Spawning success has stringent environmental requirements • Fish are highly selective in their use of spawning habitat in lakes and their tributaries • Lithophilic species require clean gravel or stones onto or amongst which to place their eggs Introduction • Arctic charr (Salvelinus alpinus ) • Schelly (Coregonus lavaretus ) • Vendace (Coregonus albula ) • All three species are lithophilic Introduction Frost (1965) Introduction Frost (1965) Introduction Bolgan et al. (2017) Introduction Introduction Arctic charr (Salvelinus alpinus ) Schelly (Coregonus lavaretus ) Red Tarn Vendace (Coregonus albula ) Introduction • In early December 2015, Storm Desmond delivered extremely high rainfall and subsequent flooding across Cumbria • Extensive and catastrophic impacts in and around many water bodies • Major movements of gravel and other substrates Introduction Introduction Introduction • The objectives of this project were: • To review pre-2015 descriptions of rare fish spawning habitat in Cumbrian lakes • To undertake new post-Storm Desmond surveys of known, putative or potential rare fish spawning habitat at selected lakes • To consider appropriate mitigation measures for sediment control in upstream catchments Methods Methods 14 lakes 9 lakes Red Tarn Surveys between January and March 2017 Methods • Underwater still photography of inshore substrate at depth of 0.5 m • Underwater videography of substrate along inshore to offshore transects at depths between 0.25 m and 10 m Methods • BioBase/EcoSound (www.cibiobase.com) combines consumer hardware and cloud computing • Produces geo-referenced data for bathymetry, macrophytes and bottom hardness • 5 or 6 inshore areas (each c. 100 m by c. 100 m) surveyed at each lake Methods Winfield et al. (2015) Results Bassenthwaite Lake (vendace) Derwent Water (vendace) Derwent Water v Bassenthwaite Lake (vendace) Derwent Water 40,000 30,000 20,000 10,000 Vendace (individuals) 0 1994199619982000200220042006200820102012201420162018 Year Bassenthwaite Lake 40,000 30,000 20,000 10,000 Vendace (individuals) 0 1994199619982000200220042006200820102012201420162018 Year Windermere North Basin (Arctic charr) Windermere South Basin (Arctic charr) Windermere South Basin v North Basin (Arctic charr) Windermere South Basin 6 ) 5 -1 4 3 2 CPUE CPUE (fish h 1 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 Year Windermere North Basin 6 ) 5 -1 4 3 2 CPUE CPUE (fish h 1 0 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 Year Ullswater (schelly) Ullswater Glenridding Beck (potential Arctic charr) Ullswater Glenridding Beck (potential Arctic charr) Summary • No evidence of any persisting impact of Storm Desmond on spawning habitats • Qualifier ‘persisting’ used because lag of c. 13 to 15 months between Storm Desmond and the present surveys, during which any immediate impacts may have been ameliorated • For example, fine sediments in vendace spawning habitats in Derwent Water deposited by an extreme flood event in November 2009 had dissipated by c. 12 months later in late 2010 • Such ‘transient’ negative impacts on spawning habitat can be tolerated by the reproductive capacity of all three species • Present surveys permitted valuable quantification of longer-term eutrophication impacts on spawning grounds Acknowledgements • Ray Valley for advice on the use of BioBase/EcoSound • Graeme McKee and colleagues of Environment Agency and Arctic charr anglers of Windermere for their log book scheme • Numerous land and fishing rights owners for access and sampling permissions • Andy Gowans and Dave Spiby of Environment Agency for securing the funding of this work and for their constructive advice and comments .